WASHINGTON (CNN) -- A new milestone was reached Thursday in the U.S. Senate, when Sen. Robert Byrd -- already the record holder for casting the most ballots in the Senate -- voted for the 17,000th time.

Although the 86-year-old staunch West Virginia Democrat has ruffled Republican feathers with unbending opposition to many of the Bush administration's top initiatives, lawmakers from both sides of the aisle gave him a standing ovation and paused to hear his reflections.

"The Senate is the forum which exists to welcome and to protect the airing of all points of view," said Byrd, looking back on 45 years in the Senate. "Both sides of the aisle need to work together to ensure that the Senate will stay true to its constitutional purpose. "We swear an oath before God and man to support and defend this Constitution. Many times I have sworn that oath. ... I have had a good run in this wonderful institution."

After serving three terms in the House of Representatives, Byrd won his Senate seat in 1958 -- and never lost it.

He established an all-time voting record in 1990 with his 12,134th ballot. In 1998 he cast his 15,000th vote. His 17,000 vote Thursday was on welfare reform.

In an at-times emotional speech, Byrd thanked "my patient and devoted wife Irma, with whom I will celebrate a 67-year-long partnership 58 days from now, Lord willing ... my talented staff for their tireless work and dedication," and the people of West Virginia, who "have expressed their faith in me time and time again. I'm proud to be their senator."

The North Carolina native, who as a poor youth worked as a gas-pumper, meatcutter and welder before winning a seat in the West Virginia Senate, lamented a change he sees taking place.

"Too often now in America, it is the size of the pocketbook that elects officials. I regret that change," Byrd said. "It keeps people out of public service instead of welcoming them into public service."

Known for an impressive grasp of history, Byrd sprinkled his speech with imagery dating back to ancient Greece. He also led the Senate in a prayer, thanking God

After him, a long list of senators took to the floor, heaping praise on Byrd as a "leader" and "mentor," and calling him the chamber's greatest authority on Senate rules.

Byrd, said Democratic Sen. Ted Kennedy of Massachusetts., "personifies what our founding fathers were thinking about. ... He brings the qualities that the founding fathers believed were so important."

"There has been no one in this body that has defended the Constitution of the United States more vigorously, tenaciously, and with greater understanding, awareness, and belief in the words of the Constitution," Kennedy added.